The present invention relates to mountain climbing apparatus, and in particular to a braking device for use with a climbing line during rapelling and in rescue operations.
In mountain climbing and similar situations it often becomes necessary to support oneself or a load on a line made fast to a rock, tree, or other point of attachment, as a person or other load is lowered by allowing controlled slippage of the line. In lowering oneself, for example by rapelling, controlled slippage of a line has been accomplished by wrapping the line around a portion of the climber's body. Increased controllability of a line during rapelling can be accomplished by also passing the line through a carabiner equipped with a brake bar. Further control has been gained by using two carabiners equipped with brake bars and interconnected by a third carabiner. This, however, has been found by some to be an awkward arrangement which is likely to twist, causing tangling of lines and reducing efficiency below that which is desired. A particular problem with the use of carabiners is that any lines secured to a carabiner may interfere with a line being slipped through the carabiner, making control of slippage uncertain.
The construction of previously known brake bars intended for use with carabiners has required that the end of a line be passed through the carabiner, around the brake bar and again through the carabiner, with the carabiner and brake bar combination thereafter being slid along a line to the desired location. As a result, an undesirable amount of time is consumed in preparing such apparatus for rapelling. Since time may be critical during a rescue operation where personnel or equipment must be passed down to an injured or otherwise stranded climber, it is important to be able to rig lines quickly for controlled lowering of personnel and equipment. Particularly in rescue operations, the need may arise for lowering unusually heavy loads quickly. In such a situation, a carabiner, because of its interrupted loop construction, may be too weak.
Lines frequently become wet, muddy, and slippery during climbing. As a result of such conditions, a carabiner and brake bar, or even two interconnected carabiners equipped with brake bars, may provide insufficient braking force to control the lowering of heavy loads.
To meet these problems, braking devices such as those disclosed in Hobbs U.S. Pat. Nos. 3,678,543, 3,695,397, and 3,757,901, have been developed. Other line-controlling devices intended primarily to permit people to lower themselves, are disclosed in Van Wie U.S. Pat. No. 194,507, Fell U.S. Pat. No. 285,603, McGowan U.S. Pat. No. 3,260,328, and Sentinella U.S. Pat. No. 4,114,726. The devices disclosed in these patents have been, however, unnecessarily cumbersome, heavy, or complex for use in mountain climbing and rescue work, and are therefore not completely satisfactory for such use.
What is needed, therefore, is a device which may be quickly and easily attached to a mountain climber's or rescuer's line, to securely and reliably control slippage of the line during lowering of personnel and equipment. Preferably such a device should be usable either in rapelling or in controlled lowering of objects from above a stranded climber, and should be resistant to tangling and twisting of lines which could produce loss of control.